Workplace Formaldehyde Exposure Linked to Cancers

The National Institutes of Health (NIH) through its National Cancer Institute (NCI) issued a release stating that results from an ongoing study of workers employed at plants that used or produced formaldehyde are continuing to point to a likely link between formaldehyde exposure and deaths from specific cancers. The cancers involved include cancer of the blood and lymphatic system, particularly myeloid leukemia.

The report provides an additional decade of follow-up data that builds on prior findings from this study and appeared in the Journal of the National Cancer Institute.

“The overall patterns of risk seen in this extended follow-up of industrial workers, while not definitive, are consistent with a causal association between formaldehyde exposure and cancers of the blood and lymphatic system and warrant continued concern. Further studies are needed to evaluate risks of these cancers in other formaldehyde-exposed populations and to assess possible biological mechanisms,” said lead author of the report, Laura E. Beane Freeman, Ph.D., NCI Division of Cancer Epidemiology and Genetics.

The NIH/NCI explained that formaldehyde is widely used in industry and as a preservative and disinfectant. The International Agency for Research on Cancer classifies this chemical as a human carcinogen, based primarily on its association with nasopharyngeal cancer. In 1995, the U.S. Occupational Safety and Health Administration (OSHA) estimated that about 2.1 million U.S. workers were exposed to formaldehyde, said the NIH/NCI.

For over two decades, the NCI has studied cancer deaths among a group of 25,619 workers, it said. The workers are predominately white males, who were employed before 1966 in 10 industrial plants that produced formaldehyde and formaldehyde resin and that also used formaldehyde to produce molded-plastic products, decorative laminates, photographic film, or plywood. A prior report derived from this study and which included data on cancer deaths through 1994 found the risk of death from leukemiasâ€”specifically, myeloid leukemiaâ€”increased collaboratively with increased formaldehyde exposure.

Researchers found a statistically significant association between death from all blood and lymphatic cancers combined, and peak formaldehyde exposure. For instance, workers with the highest peak exposures had a 37 percent increased risk of death compared to those with the lowest peak exposures. This represents an excess risk of death from several specific cancers: Hodgkinâ€™s lymphoma, multiple myeloma, and myeloid leukemia, which is most often associated with chemical exposure. The risk of death from myeloid leukemia was 78 percent higher among industrial workers with the highest peak exposures.

Excess risks of death from myeloid leukemia have also been reported among pathologists, embalmers, and other professionals who experience high-intensity peak exposures to formaldehyde. “We know that various groups of professionals who may experience high peak exposures to formaldehyde are at increased risk of leukemia, but the evidence from studies of industrial workers, among whom exposure levels and patterns may be more variable, has been conflicting. The fact that we see an excess in this study of industrial workers, which is both the largest and the one with the most extensive exposure assessment, is notable,” said Beane Freeman. Of note, agents that cause leukemia are known to be associated with chromosomal aberrations in the peripheral blood cells of humans. This study is the first to report a statistically significant link between a chemical exposure and increased risk of death from Hodgkin lymphoma.